Multiplexing refers to the ability to analyze (e.g., detect) more than one, and preferably many, different substances simultaneously. The ability to perform a multiplexed analysis would be advantageous to a number of applications such as proteomics, clinical analysis of body fluids, biodefense, and the like. Applications involving a limited amount of sample or a low concentration of the substances to be detected particularly benefit from multiplexing capability. To be useful, multiplexing systems should demonstrate a high sensitivity, a wide dynamic range, and significant multiplexing capability.
Assays using Luminex® beads in liquid arrays reportedly provide multiplexing of 100 and detect protein at a concentration as low as 10 pM [1]. This bead-based system can also reportedly detect pathogens such as bacteria and viruses. This system can interrogate several thousands of beads per second using a Luminex® LX-100 flow cytometer (Luminex Corp., Austin, Tex.). Collecting sufficient information on approximately 100 different types of beads is reportedly estimated to take about fifteen seconds [1]. However, overall analysis time is limited by the interaction of bead-immobilized antibodies with their respective antigens (i.e., the binding time). The binding time is estimated to be at least 30 minutes and can be even longer if higher sensitivity is required.
There exists a need for a system that provides faster analysis without compromising sensitivity, dynamic range and multiplexing capacity.